This hole itself has the pronunciation of "ほら". In the word bone hole, the bone hole (ほつ) promotes pinyin and semi-voiced, so it is called "こっぽら".

All pronunciations of the hole

voice

ズヅヅヅ (off-balance sheet)

Chinese pronunciation: トウ (トウ) (off-balance sheet)

Idiomatic sound: ドウ (ドウ)

cultivate

List of commonly used Chinese characters

ほら

Off-balance sheet of commonly used Chinese characters

とう